1. Field of the Invention
The invention relates generally to the field of photography and more particularly to film cassettes for roll film.
2. Description of the Prior Art
Light-trapped metal or plastic containers for a length of film to enable it to be loaded into a camera in full light are well known.
In the standard 35 mm type cassette, such as manufactured by Eastman Kodak Company, the filmstrip is stored in roll form on a flanged supply spool rotatably supported within a cylindrical cassette shell. A leader portion of the filmstrip, approximately two to two and one-half inches long, projects from an exterior end of a slit or "mouth" of the cassette shell defined by a a relatively short pair of lip-like substantially parallel extensions of the shell. A light-trapping velvet or plush lines the interior sides of the lips and usually protrudes slightly beyond respective forward tips of the lips. When the film cassette is placed in the loading chamber of a camera, the leader portion is either manually or automatically grasped to draw several inches of the filmstrip from the cassette shell to wind the leader portion onto a take-up spool in the camera.
A problem inherent in conventional cassettes is that the leader portion may be inadvertently wound into the cassette shell before the filmstrip is exposed in a camera. Once the leader portion is lost in this way, it is very difficult to retrieve.
3. The Cross-Referenced Application
The application cross-referenced above discloses a film cassette wherein a filmstrip in roll form is stored within the cassette shell and has a leader portion that projects from an exterior end of a film passage slit in the cassette shell to permit the filmstrip to be drawn out of the shell. According to the invention, a tow bar is secured to the leader portion. The tow bar normally is positioned in covering relation with the exterior end of the film passage slit to prevent the leader portion from being moved into the cassette shell and includes engageable means which may be engaged in a camera, for example, to separate the two bar from the cassette shell to draw the filmstrip out of the shell for exposure purposes.